Enzymatic Kit Research Articles

Renewable Sources and their Applications in Biotechnological Processes

Brazil has edaphoclimatic conditions to produce a diversity of crops with energetic potential. Thus, the study aims to correlate the technological parameters of biomasses suitable for fermentation, quantify metabolites produced by yeast FT-858, as well as assess the yield and fermentative efficiency for bioethanol production. It was performed studies of technological qualities of the biomasses and fermentative capacity test. For metabolites production, the yeast FT-858 was pre-grown in liquid medium (YPD 2%), recovered and inoculated in the substrates, and aliquots were collected for analysis of ethanol concentration by gas chromatography and glycerol accumulation by enzymatic kit of triglycerides. The yield and fermentative efficiency were assessed by consumption of sugar using DNS method, and ethanol density using digital densimeter. According to the results, the yeast presented better performance in saccharine sorghum, which also presented more expressive values of fermentative efficiency and yield. Saccharine sorghum has great bioenergetic potential and can be used as complement to sugarcane to increase ethanol production.

Electrochemical flow injection analysis for the rapid determination of reducing sugars in potatoes

Non-enzymatic electrochemical sensors for the monitoring of reducing sugars in foods has great potential as a rapid in-situ detection method. This development involved the assembly of a nanoporous platinum structure on a screen-printed carbon electrode (SPCE). The modified electrode was then employed as an amperometric sensing element in a flow injection analysis (FIA) manifold. The system was successfully applied to the rapid detection of reducing sugars in potatoes, without the need for sample preparation. Optimal signals were achieved in phosphate buffer (pH 7.4) at a flow rate of 0.5 mL min−1 and an applied potential of 0.6 V. Experimental results demonstrated the sensor’s long-term stability and high selectivity for reducing sugars. This method provides high sample throughput due to a rapid response time of less than five seconds. Reducing sugar values determined were in good agreement with those recorded using a commercially available enzymatic assay kit.

Freeze-Dried Cattle Meat Improves the Measurement of Total Cholesterol

The objective of this study was to propose an adaptation to the measurement methodology using enzymatic kits with raw meat and compare the efficiency in the quantification of total cholesterol in raw and freeze-dried meat, in order to optimize the execution of the analysis and the estimation of the results obtained. We used the longissimus thoracis and semitendinosus Nellore muscles which were acquired in a commercial slaughterhouse. They were ground with a food processor and separated; one of these parts was freeze-dried and the other was kept raw. The methodology purposed in our research (using freeze-dried meat), obtained better measures for cholesterol levels in both muscles. The total cholesterol measures for longissimus thoracis and semitendinosus with freeze-dried meat were 12% and 13% higher comparing to raw meat, respectively. The utilization of freeze-dried meat was more effective on the extraction and measurement of total cholesterol in both muscles.

Quercetin Ameliorates Lipid and Apolipoprotein Profile in High-Dose Glucocorticoid Treated Rats.

ResumoFundamento Os glicocorticóides (GCs) são amplamente prescritos para o tratamento de numerosos distúrbios clínicos devido às suas propriedades anti-inflamatórias e imunomoduladoras, e um dos efeitos indesejáveis mais comuns desses medicamentos é a dislipidemia.Objetivo Avaliar o efeito da quercetina, um flavonoide derivado de plantas, no perfil lipídico de ratos tratados com glicocorticóides em altas doses.Métodos Um total de 32 ratos Sprague-Dawley foram distribuídos aleatoriamente entre quatro grupos (8 ratos por grupo) e tratados por 6 semanas com uma das seguintes opções : (i) solução salina normal; (ii) 40 mg/kg de succinato sódico de metilprednisolona (MP); (iii) MP + 50 mg/kg de quercetina; (iv) MP + 150 mg/kg de quercetina. O MP foi injetado por via subcutânea e a quercetina foi administrada por gavagem oral 3 dias por semana. No final do estudo, o perfil lipídico dos animais foi medido através de kits enzimáticos. Os dados foram analisados e a significância estatística foi estabelecida em p <0,05.Resultados Os níveis séricos médios de colesterol total (CT), triglicerídeos (TG) e LDL aumentaram drasticamente em animais tratados com GC em comparação com o grupo controle. Ambas as doses de quercetina (50 e 150 mg/kg) melhoraram o CT (43% e 45%), LDL (56% e 56%) e TG (46% e 55%, respectivamente). A razão Apo B/A1 diminuiu mais de 20% após a ingestão de Anti-Inflamatory Agents.Conclusões Esses dados sugerem que a ingestão de quercetina Quercetin; induzida por glicocorticóides. (Arq Bras Cardiol. 2020; 115(1):102-108)

Analysis of rs4420638A/G and -317H1/H2 polymorphisms of APOC1 gene among Chinese patients with pre-eclampsia

To assess the association of apolipoprotein (apo) C1 (APOC1) gene rs4420638A/G and -317H1/H2 polymorphisms with the risk of pre-eclampsia (PE) and the influence of their genotypes on the clinical and metabolic indexes among Chinese women. In total 289 PE patients and 824 women with uncomplicated pregnancies were included. The rs4420638A/G genotype was determined by a Taqman real-time PCR allelic discrimination assay. The -317H1/H2 genotype was measured through PCR and restriction fragment length polymorphism analysis. Serum lipid and apo levels were measured by an enzymatic kit and a PEG-enhanced immunoturbidimetric assay. Allelic and genotypic frequencies of the APOC1 gene rs4420638A/G and -317H1/H2 were not significantly different between the two groups (all P> 0.05). However, patients carrying the G allele of the rs4420638A/G locus had higher serum levels of triglyceride, non-HDL-C and apoB, and a higher apoB/apoA1 ratio compared with those with an AA genotype (all P< 0.05). Patients carrying the H2 allele of the -317H1/H2 polymorphism had smaller delivery gestational weeks compared with those with the H1H1 genotype (P< 0.05). Polymorphisms of the APOC1 gene rs4420638 and -317H1/H2 sites may be associated with abnormal lipoprotein metabolism among Chinese patients with PE, though no association was found between variants of the APOC1 gene and the risk of PE among them.

The Effect of Turmeric Extract (Curcuma zedoria) on Antioxidant Enzymes Activity

Background: Indonesia is a country that has diversity of spices and types of cuisine. In the early 70s, the use of MSG (monosodium glutamate) as a flavor enhancer began to be popular in Indonesia. It replaces natural flavor such as sugar, salt or spices because its affordable price compared to natural flavor. MSG as food additive is added to foods that exceed limits and may cause a negative effect to the body. One of the effects is the increasing of free radicals that can lead to various degenerative diseases such as blood vessel disorders and others. White turmeric is a common spice that widely used by Indonesian. Several studies have reported the benefits of white turmeric as an antifungal, antimicrobial and so on. The objective of this research is to find the effects of white turmeric extract in improving endogenous antioxidants to suppress the free radical effects because of the excessive use of MSG.Materials and Method: We measured the activity of SOD, catalase and GSHreductase as endogenous antioxidants in mice treated with MSG and white turmeric. The subjects of this study used 24 Sprague Dawley male rats aged 2-6 months; weight 100-150 grams, which were randomly divided into 6 groups. The control group did not receive any treatment. The MSG group was given MSG (4800mg / kg/ day). Groups 3 and 4 were given MSG and white turmeric extract, respectively (100 mg / kg / day and 200 mg / kg / day). Groups 5 and 6 were given MSG and vitamin C respectively (250 mg / kg / day and 500 mg / kg/ day) after 14 days of treatment; the activity of enzyme measured by Abcam Enzyme Kit and detected by Spectrophotometer Thermo Scientific Multi-scan Go.Result: The administration of white turmeric extracts will increase SOD and Catalase activity, and reduce GSH-reductase activity.Conclusion: White turmeric extract will help the work of endogenous antioxidant enzymes in counteracting free radicals produced from MSG metabolism.International Journal of Human and Health Sciences Vol. 05 No. 01 January’21 Page: 31-34

Influence of wheat variety and dough preparation on FODMAP content in yeast-leavened wheat breads

FODMAPs are fermentable oligo-, di, and monosaccharides and polyols, which can have adverse effects on human health. Especially in individuals with gastrointestinal disorders such as irritable bowel syndrome, ingestion of FODMAPs may trigger or aggravate symptoms like abdominal pain, bloating, or diarrhea. Our objectives were to investigate the FODMAP content in the flour of 21 wheat varieties and in their 42 yeast-leavened breads prepared with a short (110 min) or a long dough fermentation (24 h), the latter according to a typical baker's recipe. Fructan, glucose, fructose and excess fructose were measured using enzymatic kits. On average, the breads of both dough fermentations had a FODMAP content reduced by > 65% compared to that of the whole grain wheat flour. Average FODMAP content of both dough fermentations was 0.22 g per 100 g fresh bread. FODMAP content tended to be lower in the long compared to the short dough fermentation, however, the difference was not statistically significant. We also found that the 21 wheat varieties differed up to five times in their potential to form FODMAPs in bread. In conclusion, the choice of a low fructan wheat variety coupled with long dough fermentation with sourdough and yeast is best to minimize FODMAPs in breads.

Technical note: Evaluation of 3 methods to determine mucin protein concentration in ileal digesta of young preweaning calves

The use of alternative sources of protein to substitute for milk proteins in milk replacers (MR) can increase the synthesis of endogenous proteins and therefore alter ileal or total-tract digestibility calculations. Mucin is the main component of gastrointestinal mucus and represents the greatest contribution to total endogenous protein. Mucin is difficult to isolate and has not been extensively studied in dairy calves. We explored 3 different procedures to analyze and estimate mucin protein (MUP) in ileal digesta of young dairy calves. Ileal digesta samples were collected from nine 30-d-old ileal-cannulated calves that were enrolled in a 3 × 3 replicated Latin square with 5-d periods. The 3 diets were a control whey protein-based MR (WPC), an isonitrogenous MR in which 50% of the protein was from enzyme-treated soybean meal (ESBM), and an N-free MR (NFREE). Mucin protein concentration and flow were analyzed by fractionation of the digesta and ethanol precipitation; this process served as the reference method. Alternative methods to estimate MUP consisted of using commercial enzymatic kits to analyze glucosamine (N-acetylglucosamine, GlcNAc) and galactosamine (N-acetylgalactosamine, GalNAc), 2 amino-sugars that are highly enriched in mucin. Before GlcNAc determination, samples were processed using 3 different procedures: sample clarification (GLCL), clarification plus hydrolysis (GLCH), and hydrolysis alone (GLHL). The MUP was estimated by regression of the GlcNAc and GalNAc values using previously validated equations. According with the bias and agreement analysis, none of the methods yielded MUP values similar to the reference method. However, GLHL showed a strong association with the reference method (ρ = 0.73). It allowed identifying the smaller MUP flows with NFREE compared with the other 2 diets and detecting the greater flow of ESBM than WPC, as observed with the reference method. Using the GlcNAc values from GLHL and the MUP measured with the reference method, we were able to establish a linear relationship between both methods (adjusted R2 = 0.75). We found that the GLHL method enabled detecting differences in MUP ileal flows between diets differing in protein level and source. Inferences about MUP secretions must be done cautiously because many dietary and physiological factors are involved. The adoption of practical techniques to determine MUP can help to increase our knowledge about gastrointestinal tract function and to improve the accuracy of MR digestibility calculations.

MP31-12 OVERACTIVE BLADDER SYNDROME IS ASSOCIATED WITH ELEVATED URINARY PRONGF TO NGF RATIO IN AN AGING FEMALE POPULATION

INTRODUCTION AND OBJECTIVE: The clinical relevance of the ratio NGF/creatinine in urine as a biomarker for overactive bladder syndrome (OAB) diagnosis is a matter of debate. ProNGF, the precursor form of nerve growth factor (NGF) was recently found to possess degenerative roles by signalling through its receptor p75NTR. The present study aims to identify the changes in concentration of NGF and proNGF, and the soluble factors involved in their proteolysis in the urine of an aging female population with OAB. METHODS: Urine samples were obtained from 20 females of 50-80 years of age with OAB and from 20 controls of the same age group. Analyses were carried out with highly specific ELISA and enzymatic kits. Participants completed a full clinical evaluation and validated self-reported questionnaires of lower urinary tract symptoms as well as a one-day voiding diary. RESULTS: NGF ELISA kit specificity was confirmed. ProNGF/NGF ratio was significantly increased in the urine of OAB subjects. Enzymatic activities of plasmin and matrix metalloproteinase 7 (MMP-7), the main enzymes responsible for extracellular processing of proNGF to NGF, were similar between controls and OAB when normalized to their respective inhibitors, α2-antiplasmin inhibitor and TIMP-1. On the other hand, metalloproteinase 9 (MMP-9), the enzyme responsible for the proteolysis of NGF into peptides, displayed a marked increased activity even when normalized to its inhibitor TIMP-1. On the other hand, nitric oxide and PGE2, two factors increasing expression and activity of MMP-9, also displayed higher concentrations in urine of OAB patients. CONCLUSIONS: The ratio ProNGF/NGF could constitute a more reliable biomarker for OAB rather than NGF level alone. This increase could originate from MMP-9 overactivity enhancing NGF proteolysis in OAB. This suggests that MMP9 inhibitors could constitute a new therapeutic target to treat OAB patients. Source of Funding: Urology Care Foundation Rising Star in Urology Research Award and the Quebec Network for Research on Aging

Fetuin-A as a Marker of Insulin Resistance in Type 2 Diabetic Patients in Zagazig University

Background: Fetuin-A is responsible for instigating insulin resistance by inhibiting tyrosine kinase receptors. Objective: To investigate the relationship of fetuin-A with and insulin resistance in type- II diabetics either obese or non-obese of Zagazig University, Shatkia Governorate, Egypt. Patients and Methods: This is a case-control study that was conducted at the Internal Medicine Department of Zagazig University. Seventy-five participants were divided into three groups. Group-A (n =25) normal healthy individual, Group-B (n =25) non-obese type 2 diabetic patients and Group C (n=25) obese type 2 diabetic patients. Type 2 diabetic patients with no morbidities. Serum fetuin-A and insulin levels were performed by ELISA kits while fasting blood glucose (FBG), 2HPP and HA1C were determined by the enzymatic kit method. A comparison of groups was done and correlation was achieved by using Spearman correlation. Results: The results demonstrated a significant difference in mean values of fetuin-A, BMI, WHR, fasting blood glucose (FBG), 2HPP, HA1C, insulin level and Homoeostasis Model Assessment of Insulin resistance (HOMAIR) in type-II diabetics when compared to normal healthy individuals and obese type-II diabetics (p<0.01). The fetuin-A level was higher in obese more than non-obese type II diabetics. Conclusion: The study concluded that fetuin-A might be accountable for insulin resistance in type-II diabetes mellitus either obese or non-obese. So the high levels of Fetuin-A responsible for insulin resistance.

Fetuin-A as a Marker of Insulin Resistance in Type 2 Diabetic Patients in Zagazig University

Background: Fetuin-A is responsible for instigating insulin resistance by inhibiting tyrosine kinase receptors. Objective: To investigate the relationship of fetuin-A with and insulin resistance in type- II diabetics either obese or non-obese of Zagazig University, Shatkia Governorate, Egypt. Patients and Methods: This is a case-control study that was conducted at the Internal Medicine Department of Zagazig University. Seventy-five participants were divided into three groups. Group-A (n =25) normal healthy individual, Group-B (n =25) non-obese type 2 diabetic patients and Group C (n=25) obese type 2 diabetic patients. Type 2 diabetic patients with no morbidities. Serum fetuin-A and insulin levels were performed by ELISA kits while fasting blood glucose (FBG), 2HPP and HA1C were determined by the enzymatic kit method. A comparison of groups was done and correlation was achieved by using Spearman correlation. Results: The results demonstrated a significant difference in mean values of fetuin-A, BMI, WHR, fasting blood glucose (FBG), 2HPP, HA1C, insulin level and Homoeostasis Model Assessment of Insulin resistance (HOMAIR) in type-II diabetics when compared to normal healthy individuals and obese type-II diabetics (p<0.01). The fetuin-A level was higher in obese more than non-obese type II diabetics. Conclusion: The study concluded that fetuin-A might be accountable for insulin resistance in type-II diabetes mellitus either obese or non-obese. So the high levels of Fetuin-A responsible for insulin resistance.

Association between Vaginal Infections and the Types and Viral Loads of Human Papillomavirus: A Clinical Study Based on 4,449 Cases of Gynecologic Outpatients.

Objective We here evaluated the association between human papillomavirus (HPV) infection and vaginal infections, including bacterial vaginosis (BV), trichomonas vaginalis (TV), and vulvovaginal candidiasis (VVC). Methods A total of 4,449 women were enrolled in this study and given gynecological examinations. HPV genotyping and viral load determination were performed using a real-time PCR. Vaginal infections were diagnosed using wet mounts of vaginal secretions, gram-stained vaginal secretion smears, and chemical enzyme kits. Results In this study, the overall HPV-positive rate was 25.06%, and vaginal infection tended to occur in women with HPV infection (P < 0.05). HPV infection tended to occur in BV- and TV-positive women (P < 0.05) and not in women with microecological disorders, intermediate type BV, VVC, or coinfection (P > 0.05). The most common genotypes were HPV58 and HPV53 in women with normal vaginal microecology and HPV16 and HPV52 in the women suffering from vaginal infection. The viral loads among groups for HPV16 and HPV52 showed no statistically significant differences (P=0.940; P=0.167). Conclusions Our study revealed that BV and TV are associated with HPV infection, especially high-risk HPV infection, while VVC has no association with HPV infection. Further studies are needed to explore the detailed mechanism.

Single-Use Printed Biosensor for L-Lactate and Its Application in Bioprocess Monitoring

There is a profound need in bioprocess manufacturing for low-cost single-use sensors that allow timely monitoring of critical product and production attributes. One such opportunity is screen-printed enzyme-based electrochemical sensors, which have the potential to enable low-cost online and/or off-line monitoring of specific parameters in bioprocesses. In this study, such a single-use electrochemical biosensor for lactate monitoring is designed and evaluated. Several aspects of its fabrication and use are addressed, including enzyme immobilization, stability, shelf-life and reproducibility. Applicability of the biosensor to off-line monitoring of bioprocesses was shown by testing in two common industrial bioprocesses in which lactate is a critical quality attribute (Corynebacterium fermentation and mammalian Chinese hamster ovary (CHO) cell cultivation). The specific response to lactate of the screen-printed biosensor was characterized by amperometric measurements. The usability of the sensor at typical industrial culture conditions was favorably evaluated and benchmarked with commonly used standard methods (HPLC and enzymatic kits). The single-use biosensor allowed fast and accurate detection of lactate in prediluted culture media used in industrial practice. The design and fabrication of the biosensor could most likely be adapted to several other critical bioprocess analytes using other specific enzymes. This makes this single-use screen-printed biosensor concept a potentially interesting and versatile tool for further applications in bioprocess monitoring.

GABA enzymatic assay kit.

We developed an enzymatic assay system enabling easy quantification of 4-aminobutyric acid (GABA). The reaction of GABA aminotransferase obtained from Streptomyces decoyicus NBRC 13977 was combined to those of the previously developed glutamate assay system using glutamate oxidase and peroxidase. The three-enzyme system allowing GABA-dependent dye formation due to the oxidative coupling between 4-aminoantipyrine and Trinder's reagent enabled accurate quantification of 0.2 - 150 mg/L GABA. A pretreatment mixture consisting of glutamate oxidase, ascorbate oxidase and catalase eliminating glutamate, ascorbate, and hydrogen peroxide, respectively, was also prepared to remove those inhibitory substances from samples. Thus, constructed assay kit was used to measure the GABA content in tomato samples. The results were almost the same as that obtained by the conventional method using liquid chromatography-tandem mass spectrometry. The kit will become a promising tool especially for the on-site measurement of GABA content in agricultural products.

The impacts of garlic and voluntary training alone or together on myocardial miR-126 and miR-210 gene expressions and angiogenesis in healthy rats.

Introduction: microRNAs (miRs) play a critical role in both physiological and pathological processes. Recent studies have shown that garlic and exercise training have many beneficial effects in different disorders including cardiovascular disease. However, their mechanisms have not been fully understood. This study sought to investigate the impact of garlic and voluntary training alone or together on themiR-126 and miR-210 gene expressions and cardiac angiogenesis. Methods: Male Wistar rats were divided into four groups (n=7): (1) Control, (2) Garlic, (3) Exercise, and (4) Garlic+ Exercise. Animals were gavaged with raw fresh garlic homogenate (250 mg/kg body weight/day) or were subjected to voluntary training alone or together for about 6 weeks. The expressions of miR-126 and miR-210 in the heart tissue were measured by real-time PCR and lipid profile in serum was assessed by enzymatic kits. Angiogenesis was determined by immuno staining detection of PECAM-1 and CD31 in the heart tissue. Results: Garlic and exercise up-regulated myocardial miR-126 (P < 0.01), miR-210 (P < 0.001)expressions, and angiogenesis (P < 0.001) which was evidenced by higher CD31 expression. Besides, combination of garlic and exercise amplified their effects on those parameters (P < 0.001). Moreover, both voluntary exercise and garlic alone (P < 0.01) or together (P < 0.001) markedly modulated serum lipid profile. Conclusion: Voluntary exercise and garlic treatment for 6 weeks enhanced myocardial angiogenesis. These alterations were partly due to the increment of miR-126 and miR-210 expressions in the heart tissue in relation to improvement in lipid profile.

Enhanced Performance of Reagent-Less Carbon Nanodots Based Enzyme Electrochemical Biosensors.

This work reports on the advantages of using carbon nanodots (CNDs) in the development of reagent-less oxidoreductase-based biosensors. Biosensor responses are based on the detection of H2O2, generated in the enzymatic reaction, at 0.4 V. A simple and fast method, consisting of direct adsorption of the bioconjugate, formed by mixing lactate oxidase, glucose oxidase, or uricase with CNDs, is employed to develop the nanostructured biosensors. Peripherical amide groups enriched CNDs are prepared from ethyleneglycol bis-(2-aminoethyl ether)-N,N,N′,N′-tetraacetic acid and tris(hydroxymethyl)aminomethane, and used as precursors. The bioconjugate formed between lactate oxidase and CNDs was chosen as a case study to determine the analytical parameters of the resulting L-lactate biosensor. A linear concentration range of 3.0 to 500 µM, a sensitivity of 4.98 × 10−3 µA·µM−1, and a detection limit of 0.9 µM were obtained for the L-lactate biosensing platform. The reproducibility of the biosensor was found to be 8.6%. The biosensor was applied to the L-lactate quantification in a commercial human serum sample. The standard addition method was employed. L-lactate concentration in the serum extract of 0.9 ± 0.3 mM (n = 3) was calculated. The result agrees well with the one obtained in 0.9 ± 0.2 mM, using a commercial spectrophotometric enzymatic kit.

Association of fetuin-A with dyslipidemia and insulin resistance in type-II Diabetics of Pakistani population.

Background & Objective:Fetuin-A, hepatokine is responsible for instigating insulin resistance by inhibiting tyrosine kinase receptors. Our objective was to investigate the relationship of fetuin-A with dyslipidemia and insulin resistance in type-II diabetics of Pakistani population.Methods:In this cross sectional study which was conducted at Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi between October 2013 to March 2014, a total of 330 participants were selected and divided into two groups. Group-A (n = 165) normal healthy individual and Group-B (n = 165) Type-II diabetes mellitus mellitus with no comorbidities. Serum fetuin-A and insulin levels were determined by commercially prepared ELISA kits while fasting blood glucose (FBG) and lipid profile were performed by enzymatic kit method. Employing independent t-test, comparison of groups was done and correlation was achieved by using spearman correlation.Results:The results demonstrate a significant difference in mean values of fetuin-A, lipid profile, glucose, insulin and Homoeostasis Model Assessment of Insulin resistance (HOMA-IR) in type-II diabetics when compared to normal healthy individuals (p<0.01). A positive correlation was found between serum fetuin-A levels and FBG(r= 0.495, p< 0.001), insulin(r= 0.227, p< 0.001), HOMA-IR(r= 0.336, p<0.001, triglycerides(r= 0.197, p< 0.001) and LDL-cholesterol(r= 0.170, p= 0.002), while negative correlation with HDL-cholesterol(r= -0.251, p< 0.001).Conclusion:The study concludes that fetuin-A might be accountable for dyslipidemia and insulin resistance in type-II diabetes mellitus mellitus. So the high levels of Fetuin-A responsible for insulin resistance might alters endothelium and causes inflammation, vasoconstriction and thrombosis and ultimately atherosclerosis.

Electrochemical determination of uric acid in urine and serum with uricase/carbon nanotube /carboxymethylcellulose electrode

The detection of uric acid in blood and urine is clinically important in terms of suitable diagnosis and self-healthcare. An amperometric thin film biosensor composed of carbon nanotube and uricase enzyme is presented. The CNT is successfully dispersed in aqueous solution with carboxymethylcellulose surfactant. This enables thin film formation by a simple drop-casting layer-by-layer process. The uricase/carboxymethylcellulose dispersed carbon nanotube/gold thin film biosensor shows the best sensing performance compared to that with sodium cholate surfactant in terms of higher current and lower detection potential. The presented procedure shows good performance with neither electron transfer mediator nor complicated process. Cyclic voltammetry exhibited a sensitivity of 233 μA mM−1 cm−2 at +0.35 V, a linear range of 0.02–2.7 mM, and a detection limit of 2.8 μM. We quantify and graph uric acid data in actual physiological samples (serum and urine) for the first time and detection values showed good agreement with those obtained by a conventional analytical method (enzymatic colorimetry kit).

Verification of Quantitative Measurement of Urinary Creatinine Enzymatic Method Kit by DIRUI CS-T240 Clinical Chemistry Analyser

Introduction: All urine samples sent for the diagnosis of inborn errors of metabolism (IEM) disorders testing will be first analysed for their creatinine levels. The urine creatinine analysis is applied either for calculation of urine amount needed in other tests or for quantitation of analytes per mol creatinine. Jaffe kinetic-end point method has been the preferred method. We aim to verify the performance of DIRUI enzymatic method reagent kit on DIRUI CS-T240 analyser and compare with Randox Jaffe kinetic-end point method reagent kit on same platform.Method: Precision study, linearity and method comparisons were carried out using three levels of internal quality control (IQC) samples and the measured results were compared against manufacturer’s claims, medical decision limit and biological variation (BV).Results: The within run coefficient variation (CV) were 3.57%, 2.61% and 1.35% for IQC Level 1, 2 and 3 respectively. The total precision and accuracy were 9.59% and 0.27% for Level 1, 3.17% and 0.57% for Level 2, while 2.03% and 3.63% for Level 3. Whereas, the verifica t ion value for CV based on analytical performance specifications (APS) BV desirable for CV and accuracy were 18.2% and 12.2% respectively. These values were compared, and the precision study was acceptable within desirable specification. Linearity met the manufacturer’s claim and range from 0.32 to 21.2mmol/L. The method comparison gave good correlation, r2 of 0.9975 and regression equation, y=0.9852x-0.022 with medical decision limit, 0.53mmol/L. The assessment of acceptability of this new method was acceptable as calculated total error (TEc) &lt; total allowable error (TEa) (APS BV Desirable for TEa = 42.1%).Conclusion: The analytical verification study that we had carried out fulfilled the BV desirable in precision, accuracy and TEa. Therefore, the performances of enzymatic method kit on DIRUI CS-T240 analyser is verified to be fit-for-purpose and can replace the existing method.International Journal of Human and Health Sciences Supplementary Issue: 2019 Page: 53

Development of a histamine aptasensor for food safety monitoring

Histamine produced by bacteria through decarboxylation of histidine in spoiled foods such as fish is known to cause food poisoning. Therefore, accurate and facile measurement of histamine is of practical importance. Using the recently discovered RNA aptamer that specifically recognizes histamine (A1-949 aptamer), we developed an aptasensor based on the structure-switching mechanism. Specifically, the aptamer A1-949 was fluorescently labeled at the 5′ end and hybridized with a short quencher DNA strand that is partially complementary to the aptamer. The quencher strand was modified with a fluorescence quencher at its 3′ terminus. Displacement of the quencher strand upon histamine binding results in an increased fluorescence. After optimizing the assay condition, the enantiomeric version of the aptasensor (L-RNA and L-DNA) was synthesized which could detect the achiral analyte with identical sensitivity and improved biochemical stability. The aptasensor performance was validated by measuring fish samples spiked with known concentrations of histamine. Finally, histamine content in spoiled fish samples was measured, and the results were compared with the measurements using a commercial enzymatic assay kit.